MARTINEZ — A Contra Costa jury on Tuesday convicted a Richmond man in connection with a violent gang rape at a Richmond park in 2001.

Tremaine David Oliver, 28, was charged with kidnapping for robbery and for sexual purposes, robbery, torture, rape in concert and forcible oral copulation in concert. The case was unsolved until a state and federal database in 2006 matched Oliver’s DNA to semen recovered from the victim’s arm.

The other attackers, in numbers unknown, have not yet been identified.

The victim testified that after she walked away from a brief conservation with two young men on the sidewalk outside Richmond’s Crescent Park on June 10, 2001, the men grabbed her from behind by the neck and dragged her into the dark park. She was 42, and Oliver was 18 at the time of the attack.

The assailants went through the woman’s pockets to rob her, and when all they found was a lighter, they began repeatedly setting her hair on fire, deputy district attorney Dana Filkowski told the jury.

Then they dragged her to a dark alcove behind the Booker T. Anderson Jr. community center and began tearing off her clothes, beating and sexually assaulting her. They kicked her and stomped on her head. The last thing the victim remembered before losing consciousness was her teeth breaking on the pavement.

She was hospitalized with head trauma after the assault and still requires a cane to walk more than a decade later, Filkowski said.

Defense attorney Barney Berkowitz argued at trial that there are too many unanswered questions and gaps in the prosecution’s case to convict Oliver beyond a reasonable doubt. While Oliver’s semen was the only such evidence found on her body, there was genetic material from at least five other men left on the victims’ clothes and two condoms left at the crime scene, Berkowitz said.

The defense attorney argued that the victim, who admitted to smoking crack earlier in the day, had consensual sex with Oliver. Filkowski said there was no evidence to support the defense’s argument.

Oliver faces life in prison. His sentencing date will be scheduled next month.

Three women have told the New York Times that music mogul Russell Simmons raped them, the latest in a cascade of serious allegations of sexual misconduct against powerful men in entertainment, media, politics and elsewhere.